As illustrated for example in Lazaro U.S. Pat. No. 3,421,993, electroplating barrels are well known for use in the electroplating of small objects. Basically, a typical electroplating barrel has a perforated wall, and is immersed in electrolyte solution while containing objects to be electroplated. The barrel is then rotated so that the objects tumble within the barrel, while submerged in the electrolyte solution, and while an electrical potential is placed across the electrolyte solution in a conventional manner to cause electroplating of the objects to take place.
Processes of this type are presently used in commercial operation. For example, coins may be electroplated with the use of a rotating electroplating barrel. However, as a disadvantage of the present electroplating barrels, when small, flat objects are being electroplated in this manner, it is possible for one or more of them to become wedged in a crack or space formed between the main body of the electroplating barrel and the removable plate or plates which serve to close the access aperture or apertures in the main body of the barrel. The access aperture provides access to the barrel interior for inserting and removing the objects to be plated. When a coin or other object to be plated does become wedged in a space between the barrel body and its closure door, such coin will not become properly plated. This defect on one or more coins can raise a significant suspicion that the entire lot of coins or other objects to be plated is defective, resulting in rejection of the lot by a purchaser.
One obvious solution to the problem is to provide closure doors for the access apertures of the barrel that fit well. However, this is not always easy, since the closure door can become useless if it is only a couple of thousandths of an inch too large for fitting into the access aperture. Thus, the closure door must be made at least very slightly smaller than the access aperture, and the natural size variation of fabricated items may cause the closure door to sometimes be too small, especially when one considers the natural variations in size of the closure aperture as it is manufactured. If the closure door is too small, the undesired crack or space between the door and the body of the barrel may appear somewhere about the periphery of the junction area of the two parts, creating the risk that a coin or other object to be plated may be able to slide into that crack as the barrel rotates.
Additionally, as the barrel rotates and is used, it is stressed and flexed, which can also cause slight variations in the size of the access aperture. Thus, inherently, it has been a very difficult proposition to create and hold good dimensional tolerance between access apertures of electroplating barrels and their closure doors so that, nowhere during long hours and days of operation can a space develop between the barrel and its closure door wide enough to permit a coin to slide in.
In accordance with this invention, an improvement in the design for the access aperture and closure door of an electroplating barrel is provided. The particular design is of a forgiving nature so that a tight contact seal may be generally provided about the entire junction between the edges of the access aperture and the closure door, even in the face of small, unplanned dimensional variations due to variations in the manufacture of the parts, or due to flexing or other stress of the electroplating barrel. Thus, the operator can be confident that small, flat objects to be electroplated will not find their way in between a gap between the electroplating barrel and its closure doors, when the doors are properly closed.